As the use of electronics on vehicles continues to gain wider acceptance, applications for electronic control grow. With these new applications comes the need to provide the electronic control module with data which is typically gathered by sensors. Sensors that are directly mounted to vehicular drivetrain components are subjected to very nigh frequency vibrations generated by transmission gearing and the like. Certain types of sensors, however, are sensitive to these vibrations and suffer from degraded performance. Additional constraints, such as the requirement of maintaining a fluid seal between the sensor and the vehicular drivetrain component further complicate the problem.
The prior art teaches various methods of isolating sensors from vibrations. For example, U.S. Pat. No. 4,469,303, issued on Sep. 4, 1984 to Snyder, discloses a vibration isolation apparatus for supporting a sensor housing on a surface to which vibrations are applied. Elastic material is placed outboard of the sensor housing and skewed therefrom to place at least one-half of the columns of elastic material in compression responsive to linear vibrations along at least two axes of the housing. Linear vibration in all three axes of the housing is reduced, improving the reduction over known methods by reducing angular acceleration about a desired axis of the sensor housing by placing the elastic material of all columns in compression or tension.
U.S. Pat. No. 4,681,293, issued on Jul. 21, 1987 to Cucci et al., discloses an isolating mount for an external vibration sensitive sensor. The vibration mounting comprises a columnar or beam member made up of a series of spaced, generally parallel shims molded into a beam with a suitable elastomeric material between the shims. The compressional stiffness of the member is high while the shear stiffness is controlled to provide a low resonant frequency and the necessary support in the linear axes of vibration. In the preferred embodiment, the spacing of the shims is increased in the central portions of the beam members to obtain a substantially linear deflection from end-to-end when the beam members are moved in shear transverse to their longitudinal axes, yet providing adequate stiffness and compression along the longitudinal axis of the separate beams.
U.S. Pat. No. 4,894,638, issued on Jan. 16, 1990 to Flierl et al., discloses a potentiometer having vibration damping means. The potentiometer has a housing divided into an outer housing and an inner housing which is largely disposed inside the outer housing. Both housings are connected by a springy damping member. The flange and the electrical terminals are retained at the outer housing and both the resistor plate and the actuator member at the inner housing. Instead of uncoupling the entire potentiometer from the object with respect to vibrations, only certain component parts that are subject to wear are uncoupled. As the outer housing is connected rigidly to the other object, the respective position in space of the potentiometer and the other object is defined clearly so that any adjusting becomes almost superfluous and faulty installation is avoided.
These existing apparatus and methods, however, have a relatively high cost associated therewith. Additionally, space restrictions, clearance problems and the like associated with direct mounted sensors often preclude use of existing apparatus and methods.